The temperature is predicted to increase in the national capital but a heatwave is not likely in Delhi until Thursday, the India Meteorological Department said on Sunday.
The minimum temperature in the city today settled at 22.2 degrees Celsius, a notch below the season's average, the weather office said.
The Safdarjung Observatory recorded a maximum temperature of 39.5 degrees Celsius today, two notches below normal for this time of the year.
The relative humidity recorded at 8:30 am was 37%.
The IMD has forecast mainly clear skies with strong surface winds during the day while the maximum temperature is likely to touch 41 degrees Celsius.
The mercury is predicted to breach the 40-degree mark tomorrow amid clear skies and gradually rise to 44 degrees Celsius by Thursday.
The IMD predicted the maximum temperature may increase by three to five degrees Celsius in most parts of northwest India during the next five days.
The mercury is likely to touch the 44-degree mark in Delhi by Thursday, it said.
The city has recorded eight heatwave days in April this year, the maximum since 11 such days witnessed in the month in 2010.
For the plains, a heatwave is declared when the maximum temperature is over 40 degrees Celsius and at least 4.5 notches above normal.
A severe heatwave is declared if the departure from normal temperature is more than 6.4 notches, the IMD stated.
Delhi had recorded a maximum temperature of 43.2 degrees Celsius on April 21, 2017. The all-time high maximum temperature for the month was 45.6 degrees Celsius on April 29, 1941.
The weather bureau had earlier said northwest India and adjoining parts of central India are likely to see more intense and frequent heatwave conditions this month.
With agency inputs
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